Writing instrument



FIG. 1 is a top plan view of a writing instrument showing my new design;

FIG. 2 is a front elevational view thereof;

FIG. 3 is a bottom plan view thereof;

FIG. 4 is a right and elevational view thereof;

FIG. 5 is a top plan view of the writing instrument in condition for use with the writing point extended;

FIG. 6 is a front elevational view thereof; and

FIG. 7 is a right end elevational view thereof. 

The ornamental design for a writing instrument, substantially as shown and described. 